<!DOCTYPE html>
<html lang="en">
<head>
	<meta charset="utf-8">
	<title>Document</title>
	<style type="text/css">
		body{
			margin:0;
		}

		.box{
			background-color: gold;
			width: 300px;
			height: 200px;
		}
		.box2{
			background-color: green;
			width: 300px;
			height: 200px;
		}


	</style>

</head>
<body>
	<div class="box">123</div>
	<p class="box2">这是一个P标签</p>

</body>
</html>